Apparatus for actuating gas-discharge lamps



United States Patent APPARATUS FOR ACTUATING GAS-DISCHARGE LAMPS Thomas Curzon, London, England, assignor to 'C. A. V. Limited, London, Engiand Application April 13, 1953, Serial No. 348,513

Claims priority, application Great Britain December 10, 1951 1 Claim. (Cl. 307-132) This invention relates to apparatus for operating a gasdischarge lamp from a battery or other low-voltage direct current source, the apparatus being of the kind comprising an energy-storing inductance and an interrupter operable by the inductance. One of the difiiculties experienced in the working of such apparatus is the erosion of the interrupter contacts when they are required to deal with a relatively heavy current, and the object of the present invention is to enable this difliculty to be minimized in a simple and satisfactory manner.

The invention comprises an apparatus of the kind aforesaid, in which the inductance comprises two or more similar windings arranged in parallel and mounted on a common iron core, and in which current-interrupter contacts are provided in association with each winding.

In the accompanying drawings:

Figures l-3 are diagrammatic representations of various gas-discharge lamp systems, each containing apparatus embodying the invention.

In the system shown in Figure l, the gas-discharge lamp is of tubular form and is indicated by a. At one end of the lamp is contained an active cathode 1) consisting of a wire coil with which are associated passive anodes c. At the other end of the lamp is contained a similar but passive cathode d with which are associated active anodes 8.

The apparatus forming the essential feature of the invention comprises the energy-storing inductance and current interrupter shown in the lower left-hand part of the drawings. The inductance in this example comprises an iron core f bent to a U-form. On one of the limbs of the core is mounted a winding g, and on the other limb is mounted a winding h. At one end the two windings are interconnected as indicated by the wire 1, and when mounted in position in the system, this wire is connected as shown through a switch 1' to one terminal of a battery k, or other source of direct current.

Across the ends of the core 1 is mounted an iron armature m which is carried by a spring blade n, the latter being supported at its ends on the ends of the core 7 through insulating abutment pieces 0.

To the armature m are secured a pair of interconnected contact pieces p which co-operate with separate fixed contact pieces q, the said contact pieces and armature constituting the required current interrupter.

In the system shown in Figure 1, the interconnected contact pieces p are connected through a wire r to the other terminal of the battery It (or other direct current source), and the contact pieces q are respectively connected by wires s, t to the other ends of the windings g, h.

The wire s is connected by a wire a to one end of the electrode d and to one side of a condenser v, and the wire I is connected by a wire w to the other end of the said electrode and to one side of a second condenser x. The other sides of the condensers are interconnected and are connected by wires y, z respectively to the ends of the electrode b and the battery k (or other direct current source) as shown.

When the system is in action, the switch j being closed, the required electromagnet energy is provided by the current flowing from the battery k (or other direct current source) through the two parallel windings g, h. The first efiect of excitation of these windings is the exertion of a pull on the armature 111 against the action of the spring n which separates the contacts p, q. With separation of the contacts the current flow is interrupted and a high voltage discharge is supplied from the windings g, h to the lamp. The purpose of the condensers v, x is to provide heating current in the active cathode of the lamp and also to limit the rise of voltage across the lamp. With interruption of the current the spring 11 returns the armature to its previous position causing the contacts p, q to re-close the circuit through the windings g, h, where the above described action is repeated, and maintained so long as the switch jremains closed.

By dividing the energizing current between a pair of inductive windings, and providing current interrupting contacts in association with each winding, the current to be dealt with by each pair of contacts can be made such as will involve a minimum of erosion of the contacts.

Instead of arranging the battery It (or other direct current source) in the system at the positions shown in Figure 1, it may be connected to the system as shown in Figure 2, and any necessary consequential changes of connections may also be made. Otherwise the description of Figure 1, however, applies equally to Figure 2.

Figure 3 illustrates a modified construction of the core f carrying the inductive windings g, h. According to this modification the core is provided with an additional and centrally arranged limb f which provides a common path for the magnetic fluxes generated in the other limbs by the windings g, it. Otherwise the description of Figure 1 applies also to Figure 3.

In Figure 3 the battery It (or other direct current source) is shown in the same positions as in Figure 1, but it may alternatively be arranged in the position shown in Figure 2.

The invention is applicable in essentially the same manner as above described to systems containing a cold-cathode lamp. Moreover, more than two inductive windings and associated interrupters may be employed, provided that the associated lamp electrode is appropriately adapted for the connection thereto of more than two inductances.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

Apparatus for intermittently interrupting low voltage current flow and creating high voltage discharges, comprising in combination an energy storing inductance having a single iron core provided with at least two limbs, and windings respectively mounted on said limbs and connected in parallel with each other, circuital means connected to said windings for receiving therefrom a high voltage discharge following each interruption of low voltage current flow through said windings, a current interrupter having fixed contacts corresponding in number and connected to said windings, and complementary movable contacts separable from said fixed contacts for interrupting current flow through each of said windings individually, and a spring-loaded armature extending across said limbs and movable by magnetic attraction resulting from current flow through said windings for intermittently separating said movable contacts from said fixed contacts, said movable contacts being carried by said armature.

References Cited in the file of this patent UNITED STATES PATENTS 2,194,288 Aust' Mar. 19, 1940 2,319,144 Lodge May 11, 1943 2,511,939 Packard June 20, 1950 

